Posted
by
Zonk
on Sunday November 05, 2006 @04:27AM
from the pass-me-the-speech-center-of-the-brain dept.

ectotherm writes "Japanese scientists have captured a dolphin with vestigial legs. Evidence, it would seem, of a land-dwelling past and observable evolution." From the article: "Fishermen captured the four-finned dolphin alive off the coast of Wakayama prefecture (state) in western Japan on Oct. 28, and alerted the nearby Taiji Whaling Museum, according to museum director Katsuki Hayashi. Fossil remains show dolphins and whales were four-footed land animals about 50 million years ago and share the same common ancestor as hippos and deer. Scientists believe they later transitioned to an aquatic lifestyle and their hind limbs disappeared. Whale and dolphin fetuses also show signs of hind protrusions but these generally disappear before birth."

When biologists uncover a squeleton from an unknown extinct species, the first question they ask themselves is : Is this a new species or a deformed member of a known species.Deformations can be caused by illness, by foetus development abnormality, by ponctual mutation.

How can they be sure this is not such a case ? This dolphin only have an extra pair of fins, couldn't this be an extreme case of conjointed twins ?

If there would be less debate about evolution in the US, I believe Fox News would have re

I think you offer up a good point. Isn't the flipper supposed to be a merged pair of legs embyologically? If so, then why is there a flipper as well? This sounds more like a HOX gene activation that shouldn't have been, or (as you suggest) incomplete twinning.

s this a new species or a deformed member of a known species.Deformations can be caused by illness, by foetus development abnormality, by ponctual mutation.
How can they be sure this is not such a case ? This dolphin only have an extra pair of fins, couldn't this be an extreme case of conjointed twins

They don't. It's just been discovered. It's only journalistic speculation. But looking at the photo, the extra fins look to be in a "natural" place, not a random growth. Thus the speculation it's an old f

The driving force behind evolution is natural selection, no one explicitly decides that species A will become B nor does A evolve into B by pure chance. If for twenty thousand years you killed off every kid who had white skin you would not have any more white people (save for freak mutations not probably even light skinned probably) that is evolution in essence.

If natural selection were purely random, there would be no speciation. I've read several books by Dawkins, and Darwin's Origin of Species and randomness, though present, is not the driving factor. There is a random variation in the gene pool of any population, but the selection process, which favors or disfavors certain traits, is far from random, and drives change in the population by predisposing individuals with certain characteristics to be more likely to leave offspring than their competitors. Yes,

I suggest Wikipedia or anything written by Richard Dawkins would reveal that evolution (in the Darwinian sense) is not easily distilled into a bumper sticker, slogan, or single image.

I don't see why that, note that I am quite familiar with genetics and so on, invalidates my example which was only given in response to the pervious posters example. All I said was that if one group has a lower survival rate then over time they will no longer be there thus the reason for no intermediates or ancestor species. It

Well okay here's a scenario where a particular colour of individual would be killed off more rapidly: moths.

There is a well documented example of evolution in action where a moth with dappled black/white wings evolved over a number of years years to become a moth with much darker, gray wings. It turned out that because of industrialisation in the town where the change was observed the trunks of a particular species of tree in that town had become much darker in colour, going from dappled to sooty grey.

But then you have dolfin A and human B but no in-between combinations (dolfin with stubbly legs)

The first and most important point is that the "dolphin with stubbly legs" *did* exist. We have the transitional fossils.

If you look back 10 or 15 million years, dolphins merge with whales. If you look back... if I recall correctly... about 50 million years, you find fossils of proto-whales with stubby legs. We have tons and tons of transitional fossils... such as whales with stubby legs... all over the entire fo

Fishermen captured the four-finned dolphin alive off the coast of Wakayama prefecture (state) in western Japan on Oct. 28, and alerted the nearby Taiji Whaling Museum, according to museum director Katsuki Hayashi.

Anyone considered that dolphins are growing hind limbs so they can go ashore to capture a few Japanese to take back to their Hominid Museum?

I really like the idea of dolphins growing new legs and coming ashore. What if they're really funny, or maybe they're really bad drunks? Now you won't be able to go into the mosh pit, 'cause some 800 pound drunk dolphin is there and he's tearing up the place.

Amid a bunch of other stuff, talkorigins has a nice photgraph [talkorigins.org] of bones from the hindleg of a humpback whale, specifically a femur, tibia, tarsus, and metatarsal. This dolphin's rear fins will be similarly composed, and not at all like fish fins in skeletal structure. It'll be pretty cool to see how it compares to other known cetacean rear legs from both modern examples and the fossil record once they X-ray the fins.

I think you need to read the aptly-timed November 2006 National Geographic article "A Fin Is a Limb Is a Wing: How Evolution Fashioned Its Masterworks". It describes how the same genes (Hox genes, if I skimmed the article correctly) shared among many otherwise very differennt creatures produce species-specific results. For example, the same genes create fins in a fish, wings in a chicken, and limbs in a human (insert graphic, page 115), or control the length (or lack of) neck in a mouse, goose, or python

HONOLULU-In an announcement with grave implications for the primacy of the species of man, marine biologists at the Hawaii Oceanographic Institute reported Monday that dolphins, or family Delphinidae, have evolved opposable thumbs on their pectoral fins.

"I believe I speak for the entire human race when I say, 'Holy fuck,'" said Oceanographic Institute director Dr. James Aoki, noting that the dolphin has a cranial capacity 40 percent greater t

Taiji, Japan, is the site of the annual ritual dolphin massacre [earthisland.org] in which fishermen drive pods of dolphins into shallow coves and stab them with spears. You should see it. It is quite a sight. The sea water turns red with blood, and the air is filled with the extraordinary sounds of screaming dolphins (they literally seem to scream).

Not picking on your comment - more just adding additional weight to it:don't forget that some plants react too when attacked - releasing chemicals into the ground to warn other plants and/or increasing the toxicity of their sap.

That's why I'm amused that you say 'vegan or hypocrite' - vegans are hypocrites too. It's just they conveniently forget that most nutritious food that they can eat is/was living at some point...

Plants at least demonstrate reactions - the original post that I made pointed out - they are aware and respond to attackers, and can warn other plants via hormones. Milk does not possess these abilities.

Milk isn't the issue -- cows are. It's a simple question of whether the production of each item causes suffering in sentient beings. Again, the concensus opinion is that plants are not sentient. Argue otherwise if you want, but it only makes you look silly. Drinking milk, on the other hand, is thought t

The key difference is that us Westerners kill cows for food and other products and we at least try to pretend we're humane about it with our stun-bolts and such. I'd rather the food I eat be borne out of as little pain and suffering as possible. Our methods may not be perfect but at least there's some reasonable purpose behind slaughtering cows and pigs. We don't mindlessly spear them in fields as part of some outdated display of self-doubted masculinity. To compare the two for purposes of apology is as

Are you certain that Westerners try to be humane in their killing ways? Do you take industrial farming to task for the way they treat their animals (to say the least, it's not humane at all)?And how can you assume that the killing of those dolphins is completely purposeless? Have you talked with the people that did it?

They kill the dolphins in that manner because its efficient. Hunter-gatherer societies often did similar things with herd animals because it was efficient. Industrial farms often treat and

PS Do you check to see whether all the meat you eat comes from animals that were humanely slaughtered? Or do you just assume it was? I can tell you right now that such an assumption is probably wrong. Do the eggs you eat come from battery-caged chickens or free-range chickens? You say you care about animals being slaughtered humanely, but do you make sure that they were?

The first? Try reading at -1. Let's not even mention that your post is far more incoherent.As far as herding animals to their death--that's happened throughout our history. It's a common technique used by hunter-gatherer societies that would herd animals over cliffs to their death.

And that's far more humane than the way industrial farms treat their animals today--and yet you're complaining about this?

Also, I did specify a preference for human survival in my post. Dolphins are often valued due to their i

That's ludicrously quixotic.To imply that someone is a hypocrite because they are against mindlessly killing intelligent beings capable of feeling pain and suffering but would also wash their hands of harmful bacteria based on the platform that 'all life is sacred' is ridiculous.

While I agree that too much stock is put in 'cute' animals by anti-cruelty organisations, the absolutist 'kill all or nothing' stance you propose is illogical, unhelpful and only serves to distract from the real acts of barbarism, s

Yeah, I respect this notion at the end of my second paragraph here [slashdot.org], but you still get my point if you substitute 'all life is sacred' with 'you shouldn't kill anything' in the original post.

It goes without saying that hunting an animal for food and treating it was reverence and respect is far removed from butchering loads of dolphins just for the hell of it.

These same nations that eat, or at least use to, live monkey brains served complete with the screaming monkey strapped to the table?

While it may be generally illegal now, my father personally witnessed it in Singapore in the late 70's and you can still see tables with holes in the center for that purpose. Compared to your East Asian nations, I'd say my culture is pretty much guilt-free.

Well, technically ID doesn't preclude common descent or vestigial organs (or limbs). ID doesn't preclude much, because it doesn't assert much, other than pointing at something or other and saying "evolution doesn't explain that." Behe himself believes in common descent, though not many of the ID advocates, many (most?) of whom are closet Creationsists, think about that much. The article would rankle Creationists, but they're already rankled by just about everything since Copernicus, so I don't see the bi

Since we have a pretty clear fossil evidence that mammals evolved on land and that the earliest mammals had legs, we can conclude the ancestors of dolphins and whales had legs. Physical evidence has been shown in rear vestigal legs, found in various stages of development (or whatever the antonymn of development is) in the fossil record of ancient whales.

The line in the summary, "Whale and dolphin fetuses also show signs of hind protrusions but these generally disappear before birth.", isn't present in the article.Also from the article:

[...Japanese researchers said Sunday that a bottlenose dolphin captured last month has an extra set of fins that could be the remains of back legs, a discovery that may provide further evidence that ocean-dwelling mammals once lived on land....]

How exactly could this be evidence of back legs? The article is pretty light on d

It seems more likely that an extra set of fins would be moving dolphin evolution forward.

Becoming a better fit for its role is what powers evolution and moves it "forward". Mutations don't have to be "forward" however. Most disease is the result of mutations. This is an example of a mutation, not of evolution - therefore this anomaly doesn't move anything "forward".

This is *one* 4-finned dolphin? Why isn't this just one of those random genetic mutations everyone is always talking about? Why does it have to be the start/end of an evolutionary path? The interesting question is, did this dolphin pro-create, and if so, did its offspring have 4 fins?

Some scientists say there may be no fish left in the oceans by 2050, and we all know that dolphins descend from a land species. We also know that dolphins are smart. I wouldn't be surprised if dolphins decided to come back on land to avoid an ocean without food (fish)!

OK, first of all, they didn't find legs. They found fins. The dolphin has two extra seemingly useless fins toward it's rear, in the same approximate location it would have legs when it walked on land.So, freak mutation causing bringing up of ancient traits encoded in dolphin DNA? Or maybe just freak mutation in general?

I mean, we've all seen the pictures of people born without legs and arms. Are you trying to tell me this is a bringing up of DNA from when we were "ball mammals", who rolled around the earth?

On the right between the bottom fin and the diver there is a grey spot that looks like it has been deliberately blurred. Are they hiding the fricken laser they just removed from its head? Maybe they've figured out that a dolphin + extra fins + laser is a more formidable weapon than a shark + laser?

An experimentalist, theorist and a mathematician are riding the TGV, bound for CERN. The train passes a field with a black sheep in it. "All sheep are black", declares the experimentalist. "No," states the theorist, "all we can say is there's at least one black sheep." "You're both wrong," declares the mathematician. "There exists at least one sheep, with at least one side black."

a bottlenose dolphin captured last month has an extra set of fins that could be the remains of back legs

Or the extra set of fins could simply mean dolphins had an extra set of fins!
What idiot has to turn everything into legs? Next they'll find a rock with protrusions and there will be the proof that rocks once walked the earth.

I'm not one, but that is neither here nor there. Believing in evolution is not mutually exclusive with believing that Christ died for your sins. Most Christians do beleive in evolution, just as they believe in an old Earth, etc. Granted, the subset of Christians who are Creationists do refer to themselves as Christian, trying to claim the label for themselves, so I know it isn't easy, but don't go insulting everyone over a few (million) oddities. That's like insulting conservatives by saying they all su

Really? Could've sworn it was the opposite. I've had *far far far far* argue the preposterous impossibility of evolution with me, and only a small handful that would even admit to speciation. You sir, seem to be the minority.

Well, the evolution naysayers think they are on a mission from God, so they're a bit more passionate. Christians who DO believe in evolution just consider it a non-issue, and aren't going to buttonhole you on the street and subject you to a tirade on the lies of Darwinism. It's like judging the pushiness of CHristians by the ones who come to your door when you're trying to eat dinner. The sample gets skewed because you only notice the pushy ones.

It is the duty of the moderate Christians, atleast a few of the vast majority, to counter the claims by the fundamentalists. If not the fundamentalists get to define Christianity by default. Same way it is the duty of the moderate Muslims to reign in the ists if they want the world to believe that Islam is a religion of peace. It is the duty of the enlightened moderate Hindus to regin in their fundamentalists and eradicate the injustices of the caste system.

Granted, the subset of Christians who are Creationists do refer to themselves as Christian, trying to claim the label for themselves

If they are a subset of Christians, then they don't need to "claim the label for themselves" - they already have it. Being a Christian does not necessarily imply that you believe in either creation or evolution - but then, the term "Christian" has become so diluted in the last century or so, that doesn't really mean much. Most Christians believe God had a hand in creation,

I think most Christians believe in evolution, and also most Christians believe in young- or old- earth creation. . That's the great thing about religious people, they have no problem believing multiple things at once, even believing two contradicting ideas at once. For example, most their lives as if there is no supernatural intervention in their everyday affairs. At the same time, they believe that supernatural entities are controlling every aspect of their lives. To carry off this dichotomy, the thei

There are christians who think, evolution might be a correct model of specification, and there are creationists, who are not christian (for instance islamic creationists). Basicly we have a new system of belief which draws ideas from jewish, christian and islamic roots (and maybe from some other roots too, some wiccans or pagans also might be creationists), whose common denominator is: Against all evidence I believe that evolutionary processes can be explained away.

By exposing supposed flaws in the evidence. Every good Creationist "knows", for example, that Mount St. Helens disproves all of thost geologic studies that calculate the age of the Earth. (Google on Creation Science St Helens for more information.)

Granted, as perhaps you can tell, I'm not the best person to explain this, but I suspect you get the idea...

Hindu Creation: At the end of the previous the universe was filled with water. On it floating on the leaf of a banyan tree was Infant Krishna, an Avatar of Vishnu. From his navel a lotus vine sprouted and bloomed. Vishnu created Brahma to create the universe. He climbed up the vine, sat on the flower and was totally confused by all that water. He said, "I dont know anything". Then Vishnu taught him all the four Vedas (Hindu scriptures). Then Brhama realized his role in the universe. He created 33 million d

If it doesn't come from the vestigial genetic code for rear fins or rear legs, it's pretty unlikely for fins to just appear out of nothing. It would probably take 100's of millions of years for that kind of change to take place. In fact it would probably just never happen. Evolution (by natural selection, as opposed to intelligent design) just doesn't work that way.

That said, if the "vestigial" fins had a use for the dolphins, and a lot of individuals had them, they could be selected for and "evolve ba

so basicly, if they found another dolphin with similar characteristics and make them breed,

Eh? You must be new to this genetics thing. You breed it with a regular dolphin, and then you breed the offspring of this pair between themselves. Voila, 3 generations and you're sure to have plenty of homozygous recessives to choose from...

There is no "planning" of evolution. For a trait to continue to be selected for, it must give an advantage at every stage. I see no selective advantage for having limbs as a fetus which are not found in the adult. You seem to be saying that they may have been in some way intelligently developing this trait because it could give them an advantage in later generations.

"...evidence that an ancestral dolphin had four fins does not necessarily mean that a dolphin ancestor lived on land..."
If the evidence stopped there, agreed. But, the evidence proceeds backwards in time to animals which lived on land and in water, and further to land-based ones.

"The fact that a mutation present in one member of the dolphin population prevents the hind fins disappearing should hardly be newsworthy."
If you understood mutation, it would be newsworthy.

> 1. I thought the theory of evolution revolved around land creatures evolving from sea creatures, not the other way around.

All land-dwelling animals developed from sea-dwelling animals. Some of these have since returned to the sea, including all marine mammals. The theory of evolution by natural selection is an explanation of the mechanisms that underly such changes.

> 2. If dolphins really did evolve from land creatures with four legs, why would they start devolving all of a sudden?

Not really. It just goes to show that dolphins with legs aren't a viable form for the dolphin to take, and so it won't be present in future species. Same as if this freak dolphin had been eaten by a shark before it mated.

In a cavern, in a canyon,
Excavating for a mine,
Dwelt a miner, forty-niner,
And his daughter Clementine.
Refrain:
Oh my darling, oh my darling,
Oh my darling Clementine
You are lost and gone forever,
Dreadful sorry, Clementine.
Light she was, and like a fairy,
And her shoes were number nine,
Herring boxes without topses,
Sandals were for Clementine.
Drove she ducklings to the water
Ev'ry morning just at nine,
Hit her foot against a splinter,
Fell into the foaming brine.
Ruby lips above the water,
Blowi